Parathyroid hormone (also abbreviated as “PTH” hereafter in the specification) is a peptide hormone produced by parathyroid chief cells and acts on multiple target organs to play a key role is maintenance of the blood calcium concentration (Furukawa, Y., “Dissection and Physiology of Parathyroid”, Saishin Naikagaku Taikei (Latest Internal Medicine System), 14, Endocrinologic Diseases 3 (edited by Inoue, H. et al), pp. 15-33, Nakayama Shoten, Tokyo, 1993).
Therefore, abnormalities in secretion of PTH bring about pathological conditions based on change of the blood calcium concentration and affections of target organs such as kidney and bone. In hyperparathyroidism characterized by unusual rise of PTH secretion, in particular, target organs are exposed to superfluous PTH, and therefore, in bones, for example, the bone metabolic turnover becomes unusual, and pathological changes of bones such as fibrous ostitis occur at the same time. Furthermore, because affections of organs include a wide range of affections such as hypercalcemia, renal calculus, ectopic calcification, pruritus, digestive ulcer, cardiac muscle abnormal contraction, brain wave abnormality and anemia, life prognosis and QOL (Quality of Life) of patients are seriously affected. As the curative medicaments for the diseases in which PTH secretion abnormally rises, activated type vitamin D and the like have already been clinically used. However, development of novel safe medicaments having further superior curative effect and being convenient for patients has been desired.